-LRB- CNN -RRB- -- Yes , Americans are stressed over the economy .

A new poll finds that Americans are sleeping less because of economic stress and demands of modern life .

Our day seems shorter , schedules are crammed and precious sleep hours are sacrificed -- tossing , turning or working .

Adding onto that is Daylight Saving Time , which begins Sunday at 2 a.m. when Americans will have to set their clocks ahead by an hour .

Released this week , the National Sleep Foundation 's annual poll estimated that Americans get an average of about 6.7 hours of sleep during a weekday .

The annual Sleep in America poll estimated the hours of sleep have gradually decreased .

Over the last decade , the poll indicates that a growing percentage of Americans is getting less than six hours of sleep and the number of people who get eight or more hours is dwindling .

The poll had a margin of error of 3.1 percentage points . National Sleep Foundation is a nonprofit organization of researchers , patients and health care facilities . It said it does not solicit or accept funding for its annual Sleep in America polls .

`` In the last few years , we 've seen the economy take a nose dive , and more people are affected by that , '' said Dr. Raj Kakar , a medical director at the Dallas Center for Sleep Disorders . `` More people are stressed . Stress is associated with sleep deprivation , anxiety , depression and sleeplessness . The economy is a major factor why people are losing sleep . ''

The findings echo a survey conducted by the American Psychological Association , which reported last year that 52 percent of 7,000 respondents were losing sleep at night from stress .

Aside from financial anxieties , in just a decade society has become more around-the clock and more complex .

`` This has been more insidious over two decades , '' Kakar said . `` With the advent of the Internet , cell phone , Blackberries , we 're seeing our society is increasingly 24-7 . People are able to be active at any time from anywhere , and it causes people to be more active around the clock . This increased activity is essentially giving sleep less importance . ''

The mean hours of sleep on a weeknight dwindled from an average of 7 hours in 2001 to 6.7 hours this year , according to the Sleep Foundation 's poll .

It could be that life in 2009 has more distractions , said Dr. David Schulman , the medical director of the Emory Clinic Sleep Disorders laboratory in Atlanta , Georgia .

So what 's taking time away from sleep ?

`` It 's been entertainment , Internet , playing games or TV . People have all sorts of distractions they did n't have back then -LRB- in previous years -RRB- , '' Schulman said .

Centuries ago , people routinely slept eight to nine hours a day , he said . But now , only about a quarter in the survey reported getting eight or more hours of sleep .

Doctors warn about the effects of sleep deprivation , such as car accidents , depression , anxiety and cardiovascular problems . Doctors recommend seven to eight hours a day . Schulman likened sleep deprivation to chronic alcoholism .

`` When you 're chronically drunk , you ca n't tell when you 're drunk , '' he said `` If you 're chronically sleep deprived , you ca n't tell when you 're sleepy . You lose the ability to detect how tired you are . It 's not unusual to fall asleep behind the wheel . ''

But there is contradicting research on how much sleep Americans are getting . John Robinson , a sociology professor at the University of Maryland , challenged the notion that people are sleeping less in the 24-7 treadmill of modern life .

`` There has been no decline in sleep . It 's been sustained , '' he said , according to time-use surveys that date back to 1965 .

Robinson , a past director of the Americans ' Use of Time Project , monitored time-use diaries to track how people spend their day . Since 2003 , the Bureau of Labor Statistics and the U.S. Census Bureau have gathered time-use information that has consistently reported that Americans sleep 8.6 hours a day .

Dr. Neil Kavey , director of the Sleep Disorder Center at New York-Presbyterian at Columbia University Medical Center , said the statistic is difficult to believe , especially from his New York City practice .

`` I ca n't believe that people get that much sleep in this busy world of ours , '' Kavey said . `` I think a lot of people need 8.6 hours of sleep , but I think very few people get it . ''

The huge disparities in the results from the Sleep Foundation 's poll and the government 's time diaries could be attributed to different methodologies , experts on each side said .

The Sleep Foundation 's annual findings are based on a telephone survey of 1,000 people in which the participants are asked to estimate the number of hours they usually sleep .

Meanwhile , the government 's time use surveys ask people to detail hour-by-hour how they spent the previous day . Between 2003 and 2005 , about 37,000 people were surveyed .

The time use surveys may overestimate sleep , because sleeplessness such as insomnia , tossing and turning and lying awake are categorized as sleep , said Dr. Chris Drake , clinical psychologist at Henry Ford Hospital Sleep Disorders and Research Center in Detroit , Michigan .

`` You may actually sleep four hours , but you 're in bed for eight hours , '' said Drake , who is a board member with the National Sleep Foundation . `` They 're counting that as eight hours of sleep . ''

Despite differences in the average hours , researchers and experts agree that stress and work rob a person of sleep .

During tough economic times , people might work longer hours to avoid the risk of running behind on their workload and the possibility of a layoff .

If a person is working more , he or she borrows that time from sleep .

`` That 's a bad loan , '' Kavey said . `` There 's a lot of bad loans going around . Borrowing from sleep is a bad way to go . ''

And modern society gets some of the blame .

`` Our society has valued people who brag about being able to function on very little sleep as a mark of someone who is aggressive , dynamic , successful , '' Kavey said . `` Well , forget that . Admire someone who puts focus on sleep and is not making mistakes -LRB- from sleep deprivation -RRB- . ''

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Annual sleep poll estimates Americans get less sleep , averaging 6.7 hours a day

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Experts : Society has become 24-7 , more complex

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Government research , private polling differ on sleep findings